Instrument for comparing and measuring rays of light.



No. 894,499. EATBNTED JULY z8, 1909.

' o. G. HINRIGHS.

INSTRUMENT FOB. GOMPARING AND MEASURING RAYS OF LGHT. l -APPLIoATIoN FILED 00T.z5, 1901.

PATENT OFFICE.

' QARL G. H1Nmc11s', or s'r.`LoUis, MissoURI.v

INSTRUMENT Fon coMiARING AND MEASURING RAYS OFLIGHT.

Specification of Letters lai'fent.-

V' Patented July 28, 1908.

applicati@ mea october es, 1907. semi No. 399,149.

To all whom it ma/y concern.' y

Be it known that I, CARL G. HINRIcHs, a

l citizen of the United States, residing at St. Louis, Missouri,- have invented a certain new and useful Im rovement in Instruments for Colm aring an Measuring Rays of Li ht, `of whic the following is afull, clear, an exact description, such as will enable others skilled in the art to which'it ap erta'ins to make'and use the same, reference ein had tothe accompanying drawings, forming part of this speclcation, in whicht' Figure 1 is a vertical sectional view of my instrument, this View being taken on Ian irregular section line; Fig. 2 is a cross sectional view of the receptacle 4of said instrument;

and Fig. 3 is a top plan view -of the instrument shown in Fig. 1. This invention relates to` photometers; namel instruments used in measuring the intensity of light or comparing the intensities of-.two lights. The main object ofmy invention is to provide an vinstrument for comparing and measurlng artiiicial ights, such, for exam le, as incandescent electric li hts and arc ights.

The artificial lig ts which are now in general use, such, for exam le, as incandescent electric li hts, and arc liglits, are known to be 1associate with heat and especially with a large amount of dark li ht or invisible rays which represent not onIy a great waste of power for their'production, but also 'exert a 1 ail'lmful influence on people who use the 1g ts. u

The mainv object of m invention is to provide an instrument by w ich the dark light or invisible rays of artiiicial lights can be made 40 visible to the human eye so that they can be comlpared and measured. i

T e `practical utility of my instrument is manifest in the fact established by theinstrument that modern electric lighfts riw in general use and found by ordinary photometer tests to be equal in intensity, actually diHer .greatly in the amount of. invisible radiation, the radiation in some lights being more than five hundred times greater thanl in others. In view of the fact that this invisible light .aliects the human system' and .is utilized by specialists for 'curative' purposes,

the advantage of being hble to compare the. invisible raysof lights and measure them 55. will be obvious.

With my instruments, which I have termed dar the dark lightl or invisible rays of.

measure *the waste of power in electric lightsJ and also the intensity of the .dark light or'invisible rays vand vthus use some "means for diminishing. If it is im osslble to prevent the production of this dar light or harmful light theinstrument will enable the engineer to selectl roper screens that sift out some of this armful dark light. 'l By means ofmy iiuophotometer a physician using these dark rays for fluophotometers, an electrical engineer canoo v 0f this dark light or avoiding 1t.

curative purposes can age or measure theV i intensity of. the power. e uses and thus be more certain of attaining the object for which he uses the rays.

While my instrument is particularly 4ada ted for comparing and measurinv the lilight or invisible rays of artificial lights it can also. be used formeasuring ordinary white light or visible light. Briefly stated, my instrument consists of a receptacle containing liuorescent bodies o1' substances and havlng a viewing opening and a plurality of light-admitting o enings so located as-to permit the passage t rough said bodies in' substances of independent dark li ht or invisible rays of two different lights, arrange my instrument 1n such a light rays. To compare and measure themanner that beams of light from said lights ,r

will pass throu h the fluorescent bodies or substances in tile receptacle of the instrument, said substances making the invisible rays of the beams of light in the receptacle visible to the human eye through the viewing o ening in the receptacle. Tlhese rays'can t en be measured in the well-known manner,

namely, by moving the receptacle till the two beams appear eciual in luminosity, measuring the distances rom the openings 1n the `sides of the receptacle tothe source of each light, and a plying the law of the inverse ratio of the istances squared.

Referringto thedrawings which illustrate my preferred iormof instrument or fluophotometer, A designates a receptacle of approximately cube-shape havinga removab top or cover and (provlded in two 'of 1t s oppositely disposed si e walls with oblong-shaped o enings 1 arranged inthe same horizontal tween which the instrument is arranged, can

Y an opening 2 through which the beams of light in the receptacile can be observed. If

desired, an ordinary reading telesco e D may be arranged over t e opening 2 in t e top of the receptacle to magnify the rays of light. The receptacle contains a fluorescent bod or substance s0 that the parallel beams of light which enter the receptacle will be visible to the human eye. Almost any of the numerous fluorescent substances, either solid or in solution. can be used. When solid fluorescent substances are used, the instrument can be adjusted or arranged in any position but with li uid fluorescent substances the instrument s ould be mounted on a level surface oi held in a level position unless the receptacle A is soconstructed that it can be completely filled with the solution. If .the receptacle A is to be completely filled the opening 2 will have a glass cover. For solution in water eesculin and bisulfate of quinin are very serviceable fluorescent substances for fluophotometric purposes, and when eesculin is used the solution should contain not more than 1/200 to 1/300 of a milligram in the cubic centimeter; that is to say, not more than four parts in a million. The most noted fluorescent body, fluorescein, is too intensely fluorescent to be used for measuring the invisible rays of artiiicial lights but it is admirable material to use in solution when the instrument is to be employed for measuring ordinary visiblelight, namely, when the instrument is to serve as a common photometer.

Since glass absorbs iluorescent light, the receptacle which contains the solution must admit the beams of light through quartz plates and therefore I prefer to arrange a quartz plate 3 over each of the openings 1 in the side Walls of the receptacle. If the instrument is to be used for obtaining only approximate measurements thin glass plates such, for example, as the cover glasses used by niicroscopists, can be substituted for the quartz plates 3, and if the instrument Ais to be usedinerely for measurin visible light with fluorescein solutions, or inary microscope slides may be used to admit the beams of light to the interior ofthe receptacle. When solid fluorescent substances are used, such, for example, as 'a transparent rectangular block of canary glass or a surface coated 'with powder, no quartz nor other plates are necessary.

As previously stated, while my instrument is particularly adapted `for comparing and measuring the invisible rays of artificial lights it can also be used as a hotometer for measuring ordinary white lig ts by increasing the amount of the fluorescent substance in the solution in' the receptacle A. It will, of course, be understood that the sha e and size of the receptacle A is immateria so far as my broad idea is concerned, but I refer to make said receptacle about one inci square and locate the o enings 1 so that the arallel rays of li ht w ich penetrate the interior thereof wi be about 11G- of an inch apart, said o enings being froml; to of an inch in wi th. While it is preferable to have the beams to 'be compared, parallel to each other, I do not wish it to lbe understood that it is necessary'to the successful operation of my instrument that the beams should be arallel. Furthermore, II do not wish it to e understood that it is necessary to arrange the li hts B and C and the instrument in a straig t line as the instrument could be arranged out of alinement with the lights B opening and a plurality of light-admitting o enings so located as to ermit the passage t rough said substance o independent light rays; substantiallyas describe 2. An instrument for comparing rays of light, comprising .a receptaclel having oppositely disposed. walls in which openings are formed, and a iluorescent body or substance inside of said receptacle; substantially as described.

3. An instrument for comparing rays of light, comprising a receptacle having openin s formed in two of its sides and so dis osed re ativel to each other :that beams of ight, preferab y parallel beams, will penetrate to the interior of the receptacle, and a fluorescent body or substance inside of said receptacle, substantially as described.A

4. An instrument for com aring rays of' light, comprising a receptacley provided in two of its side walls with openings which are so located relatively to each other that parallel beams of light can enter the rece tacle, pieces of glass or quartzl covering sai openings, and a fluorescent bod or substance insi e of said receptacle; su stantially as described.

' 5. An instrument for comparing rays of light, comprising a receptacle provided in its top with an o ening and in two of its o positely disposed) side Walls with openings w ch are offset` or staggered relatively to each other, and\a fluorescent body or substance inside of said receptacle; substantially as described.

6. An instrument for comparing rays of.

inside walls' of which are blackened, said receptacle being provided in tWo of its oppositely`y` disposed sides with openings through which beams of light can penetrate to the interior of the receptacle, and a :fluorescent body or substance inside of said receptacle; substantially as described.

7. An instrument for com aring rays of light, comprising a rectan ar-shaped receptacle provided in its top with an opening, a magnifying device arranged over said opening, two of the oppositely disposed side Walls of said receptac e being provided with rectangular-shaped openings which are located in approximately the same horizontal plane 15 but in different lateral planes, and a fluorescent body or substance inside of said rece tacle; substantially as described. I lin testimony whereof I hereunto affix my signature in the presence of two Witnesses, 20

this twenty second day of October, 1907. CARL G. HIN'RICHS.

Witnesses:

, WELLS L. CHURCH,

GEORGE BAKEWELL. 

